Composite number

Elastomer

Fabrication

Materials science

Layer (electronics)

Inkwell

3D printing

Flexible electronics

Carbon fibers

Alternative medicine

Nanotechnology

Carbon nanotube

Electronic skin

Sheet resistance

Conductive ink

Composite material

Silicone

Medicine

Heating element

Polydimethylsiloxane

Polymer science

Pathology

Electrical conductor

Advanced Functional Materials

3D printing of conductive elastomers is a promising route to personalized health monitoring applications due to its flexibility and biocompatibility. Here, a one‐part, highly conductive, flexible, stretchable, 3D printable carbon nanotube (CNT)‐silicone composite is developed and thoroughly characterized. The one‐part nature of the inks: i) enables printing without prior mixing and cures under ambient conditions; ii) allows direct dispensing at ≈100 µm resolution printability on nonpolar and polar substrates; iii) forms both self‐supporting and high‐aspect‐ratio structures, key aspects in additive biomanufacturing that eliminate the need for sacrificial layers; and iv) lends efficient, reproducible, and highly sensitive responses to various tensile and compressive stimuli. The high electrical and thermal conductivity of the CNT‐silicone composite is further extended to facilitate use as a flexible and stretchable heating element, with applications in body temperature regulation, water distillation, and dual temperature sensing and Joule heating. Overall, the facile fabrication of this composite points to excellent synergy with direct ink writing and can be used to prepare patient‐specific wearable electronics for motion detection and cardiac and respiratory monitoring devices and toward advanced personal health tracking and bionic skin applications.

3D Printable One‐Part Carbon Nanotube‐Elastomer Ink for Health Monitoring Applications